1. Field of the Invention
The present invention relates to a read/write head and an information storage device, and more particularly, to an electric field read/write head, a method of manufacturing the same, and an information storage device comprising the electric field read/write head.
2. Description of the Related Art
In general, magnetic recording type HDDs (hard disk drives) adopt a magnetic recording method. However, since a magnetic field has a loop shape, it is difficult to generate a strong local magnetic field using a magnetic recording type read/write head, that is, a magnetic read/write head. Due to this restriction, there is a limit in increasing a recording density using the magnetic recording method.
To overcome the limit in the recording density of the magnetic recording type HDDs, researches on a read/write head using an electric field, that is, an electric field read/write head, and a ferroelectric recording medium on which data is recorded by an electric field have been conducted. Since local write energy (an electric field) that is stronger than that in the magnetic recording method, can be generated using an electric field read/write head, the recording density can be increased to be over 1 Tb/in2.
FIG. 1 illustrates a conventional electric field read/write head. Referring to FIG. 1, a resistance sensor having a source S1, a drain D1, and a channel C1 therebetween is provided on a Si substrate 1. An insulation layer 2 and a write electrode 3 are sequentially provided on the channel C1. An electrical domain can be polarized into a first direction and the opposite direction thereof (hereinafter, referred to as the “second direction”) on a surface of a recording medium by applying a write voltage to the write electrode 3. The electrical domain polarized into the first and second directions can respectively correspond to data “0” and “1”. During a read operation, the channel C1 is located on the polarized electrical domain and a current between the source S1 and the drain D1 is measured. Since the amount of current changes according to the polarization direction of the electrical domain, information written to the electrical domain can be determined.
However, the conventional electric field read/write head has the following problem. During the manufacturing of the conventional electric field read/write head, the thickness of the channel C1 is controlled according to a condition of an ion implantation process. In this case, it is difficult to control the thickness of the channel C1 to be thin. As the thickness of the channel C1 decreases, the resolution of the resistance sensor is improved according to a head movement direction, that is, a direction parallel to a track (hereinafter, referred to as the “track direction”). Considering this fact, it is difficult to implement the resistance sensor exhibiting a superior resolution with conventional technology. When a plurality of resistance sensors are formed on a single Si wafer, it is highly likely that the thickness of the channel C1 changes according to a location, in the conventional technology. Thus, it may be difficult to secure reproducibility and regularity of the conventional field read/write head according to the conventional technology.
Also, to increase the resolution of the resistance sensor in the track direction that is, the head movement direction, a shield layer is preferably provided at both sides of the channel C1 according to the track direction. In the conventional structure as shown in FIG. 1, it is difficult to form a shield layer in the substrate 1, under the channel C1. Accordingly, during a read operation, it is difficult to block an effect of magnetic field interference generated around a certain recording area where information is to be read.
In addition, in the conventional electric field read/write head, the sensitivity of the resistance sensor can be deteriorated due to a drain induced barrier lowering (DIBL) effect. That is, a depletion region of the drain D1 increases a drain current so that the sensitivity is lowered, and this problem can be serious as the length of the channel C1 decreases.